High flexibility of an industrial robot can meet various special requirements in the modern green casting production, and adoption of the robot in the casting production not only can liberate operators from heavy and tedious manual labor and save labor, but also is the important means for improving production efficiency, manufacturing accuracy and quality for a casting and implementing mechanization, automation and civilization of casting production. Currently, adoption of advanced applicable new casting technologies, and improvement of the automation level of casting equipment, particularly application of a movable robot technology are key measures for casting enterprises to implement green casting production and realize sustainable development. Casting is carried out in harsh environments with a high temperature, a large amount of dust, vibration, oil stain, noise and electromagnetic interference, and the casting has a heavy weight, and thus, a common industrial robot cannot meet production requirements. If a casting robot is expected to be suitable for such working environments and normally run, there are still numerous key technologies in urgent need of research and breakthrough. The casting robot not only can be used for casting carrying and transfer in the die-casting and precision-casting production, but also can be used in processes of shaking, core making, core setting, pouring, clearing, inspection and the like of sand casting. Particularly, in the production of a middle-to-large sized castings, sizes and weights of both a sand core and the casting are relatively large, and for execution of core taking, core assembling, core setting, pouring and carrying operations, the difficulty is great with a high requirement. A high-flexibility heavy-load type casting robot which can meet requirements for the core taking, core assembling, core setting, pouring and carrying operations in the casting production is urgently required.
Currently, most of robots used in the casting production are articulated serial robots, which have the advantages of simple structure, convenience for control and large working space, but are poor in accuracy and low in load capacity and can only execute a light-load operation task. The articulated serial robot is difficult to meet the heavy-load operation task requirements in the middle-to-large sized casting production, and improvement on operation accuracy and efficiency is limited. Application of the existing casting robot is also limited to a case for assisting in completing a relatively simple casting operation task at a fixed station, and cannot adapt to the movable accuracy operation requirement in the complex operation environment of the casting production. For example, a serial pouring robot used in the production is simple in structure and low in cost, but cannot meet use in diversified places due to excessively few freedom degrees and the single application place. Casting robots generally applied are all obtained by remanufacturing common robots. Currently, for many small-to-middle sized casting manufacturers, when operations of core taking, core assembling, core setting, pouring and the like are carried out in the production process, the huge-crowd strategy is usually adopted, one worker carries out core taking, core setting, core assembling and melt pouring at one station, and the worker has to run back and forth, so it seems very busy and disordered and meanwhile, working efficiency is low. The operation for carrying the sand cores and the castings is mainly completed by manually simple assisting lifting equipment, and in few technical solutions in which the robot are adopted, mainly the serial robot at a fixed position is equipped with a pneumatic gripper to carry out operations, lack of a professional movable heavy-load casting robot. Particularly, in the pouring operation process of the middle-to-large sized casting, labor is still mainly adopted, with high labor intensity of the worker high physical output, and a low working efficiency. In the pouring process, molten iron or molten steel is transferred onto the production line by a casting ladle, and is aligned with a sprue gate, so that the molten iron or the molten steel in the casting ladle is poured into a pouring riser of a pouring workpiece. Currently, pouring the molten iron or the molten steel is performed by the following process: carrying by workers or lifting by a travelling crane the heavy casting ladle to receive the molten iron or the molten steel from a high-frequency furnace, then moving 150 to 200 kg molten iron or molten steel in the casting ladle to the pouring place, and slowly inclining the casting ladle by cooperation of two or more people so as to pour the molten iron or the molten steel in the casting ladle into the sprue gate of the workpiece. Such method has the following defects: (1) due to the load of the worker, the size (weight) of a casting part is limited, and when one casting needs to be casted in very short time, if two or more ladles of molten iron or molten steel are adopted, due to the low speed of the worker, the made casting is prone to casting defects such as the quality problems and the like; (2) labor intensity of the worker is high, the working environment is harsh, a temperature of the molten iron or the molten steel reaches about 1,500° C., a working environment temperature for the worker is above 40° C., and the worker is easy to feel tired due to high labor intensity; (3) the working environment is dangerous, the worker should be always careful of splashing of the molten iron or the molten steel, and there are hidden dangers for worker's personal safety; and (4) in the working process, a transport speed and a pouring speed are low, with a low working efficiency, and a low productivity, thereby increasing a manufacturing cost and delaying the manufacturing progress.
Aiming at the problems of the casting in the operations of core assembling, core setting, pouring and carrying, existing patents also provide some solutions. The Chinese Patent Publication No. 201610698460.5 discloses an automatic pouring robot which includes a power device, a transmission device, a scooping device, a detection device and the like and can control a rotating speed and angle of a scoop, but for this solution, only simple scooping and pouring can be carried out, a working space of the robot is small, and production efficiency is low. The Chinese Patent Application No. 200910015467.2 discloses an aluminum piston pouring robot, a main swing arm, an auxiliary swing arm, and a vertical swing arm and connecting bars of the pouring robot form a parallel four-bar mechanism, which can meet the follow-up pouring process requirements that an aluminum piston blank casting is tilted forward or backward, but for this solution, flexibility is poor, a time interval for actions is long, production efficiency is low, repeatability precision for a weight for scooped aluminum liquid and positioning accuracy for the scooped aluminum liquid are poor, and product quality is instable. The Chinese Patent Application No. 201610072679.4 discloses a pouring device controlled by a robot, the device is driven by adopting a bevel gear, a compressed air cooling pipeline and a fan continuously cool down the pouring device, but meanwhile, a cooling effect is also performed to pouring liquid, so that production quality is reduced. The Chinese Patent Application No. 201611165409.4 discloses a high-accuracy aluminum piston pouring robot which includes an ABB six-axis industrial robot and a pouring robot and has the characteristics of multiple freedom degrees, high system flexibility and the like, but this solution adopts a serial robot arm, the working space is small and the movement process is instable, so that pouring quality is influenced. The Chinese Patent Application No. 200710012538.4 discloses a novel parallel pouring robot which includes a base, a revolute joint, a rotary wheel, a machine body and a casting ladle, ensures accuracy for liquid taking by a volume method and drives a set of parallelogram four-bar mechanism by a motor to enable the casting ladle to swing in a certain range so as to implement positioning of the casting ladle, but accurate positioning cannot be ensured in other directions, and the working space of the robot is small. The Chinese Patent Application No. 201320665695.6 discloses a four-joint scooping or pouring robot, and the equipment is simple in structure and cannot carry out complex pouring work and is low in positioning accuracy and low structural bearing capacity in the pouring process. The Chinese Patent Application No. 201120359585.8 discloses a robot double-casting-ladle pouring arm which includes a pouring arm, a supporting frame, servo motors and a speed reducer, two motors respectively drive two casting ladles to carry out pouring by chain transmission systems, production efficiency is improved, but meanwhile, positioning accuracy becomes poor, and a spacing between two casting ladles is non-adjustable, so that the robot double-casting-ladle pouring arm is only suitable for a small-sized casting. The Chinese Patent Application No. 201510444411.4 discloses a movable ground rail pouring manipulator, a base is mounted below the pouring manipulator, and is moved on the ground rail by sliding wheels, but the working track is limited by the rails and flexibility is poor. The Chinese Patent Application No. 201621367895.3 discloses a design solution of a piston one-machine two-mode full-automatic casting machine which adopts a serial pouring robot at a fixed position and a simple part-taking hand to complete tasks of taking the aluminum liquid, pouring and taking the casting and is suitable for a light-load operation at a fixed position on a production line.
In the aspects of core taking, core assembling and core setting, the Chinese Patent Application No. 200920140832.8 discloses a casting core setting device including a sand box, a sand box positioning assembly and a serial manipulator for clamping a core and the like, the manipulator can only operate in a defined range, an actuator for clamping a sand core adopts a clip plate structure, and the casting core setting device can only meet the operation requirements of the single sand core. The Chinese Patent Application No. 201520331028.3 discloses a robot device for automatic core assembling which includes a sand core placement sliding table and a gripper working at a fixed position, a supporting seat, an adjusting eccentric wheel, a positioning wheel and a photoelectric detection switch are arranged on the sand core placement sliding table, a glue injection device and a detection device are arranged on the gripper, a plurality of glue guns are arranged on the glue injection device, the technical solution only simplifies structures of the glue injection device and the detection device and implements integration of the two functions, the whole device cannot move, the working range is limited, and the operation requirements of a special-shaped sand core cannot be met. The Chinese Patent Application No. 201610325766.6 discloses a base-type robot core setting and part taking mechanism which includes a pouring mechanical arm and a core setting and part taking mechanical arm, and although the requirement for the radius of the three-station core assembling operation can be met by an arranged three-station core assembling rotation platform and labor intensity of staffs is reduced, the operation range and objects are still limited by a fixed position of a robot and a simple end actuator. The Chinese Patent Application No. 201611053848.6 discloses a core taking and core assembling robot gripper which includes a control module, a gripper frame, a connecting flange, a clamping mechanism module on left of the gripper, a linear sliding block guide rail, a clamping mechanism module in the middle of the gripper, a pneumatic servo translation mechanism and a clamping mechanism module on the right of the gripper and can simultaneously clamp one, two or three sand cores on the left, in the middle and on the right, when each module independently performs a gripping action, the rotation of the sand core can be implemented by a pneumatic rotating module, but the core taking and core assembling robot gripper has the defects that in the gripping process, the sand core can only be clamped by a movable end clamping arm module, and when a relatively heavy sand core is gripped, not only there are few clamping points, but also the sand core needs to be moved, so that the sand core is easy to damage.
As the casting technology is improved, there are more and more requirements for production of middle-to-large sized castings and automation of operations of core taking, core assembling, core setting, pouring and carrying in the cast forming process. In the existing technical solutions, mostly the serial manipulator at a fixed station is adopted to carry out operations, not only the operation range is small and the movement is limited, but also load capacity is low, and the requirements for the operations of core taking, core assembling, core setting, pouring and carrying of the middle-to-large sized castings cannot be met.